AMPLIFIER UNIT FOR A SOUND TRANSDUCER AND SOUND GENERATION UNIT

Description

[0001] The present invention relates to an amplifier unit for a sound transducer, in particular a MEMS sound transducer, which can be operated as a microphone and as a loudspeaker, with at least one audio amplifier for sound reproduction and / or sound recording. The invention further relates to a sound generation unit with a sound transducer, in particular a MEMS sound transducer, which can be operated as a microphone and as a loudspeaker, and an amplifier unit coupled to the sound transducer for sound reproduction and / or sound recording.

[0002] Devices and methods for noise reduction, so-called "active noise reduction" (ANR) or "active noise cancelling" (ANC) methods, are known in the prior art. Such devices are, for example, arranged in headphones or headsets, whereby disturbing ambient noise is reduced by first picking it up with a microphone located on the headphones. From the picked-up sound signal, the device generates an anti-noise signal that matches the ambient noise, which is played back by a speaker in the headphones in addition to the music. The anti-noise and the ambient noise cancel each other out through destructive interference, so that only the music, and in particular no ambient noise, reaches the wearer of the headphones.

[0003] A device comprising a microphone and a driver assembly is known from US patent 2016 / 0182987 A1. The device includes a microphone driver and a loudspeaker driver, which drive a transducer that can function as both a microphone and a loudspeaker. A disadvantage of this device is that it cannot be used for ANR (Active Noise Reduction) procedures.

[0004] US patent 2006 / 0034472 A1 discloses a circuit that can operate a MEMS microphone or a MEMS loudspeaker.

[0005] US patent 2008 / 0170515 A1 describes a circuit for operating a single transducer.

[0006] The object of the present invention is therefore to create a device with which ambient noise can be effectively suppressed.

[0007] The problem is solved by a sound-generating unit with the features of the independent patent claim.

[0008] A MEMS transducer is proposed, which can be operated as both a microphone and a loudspeaker and is coupled to an amplifier unit. The amplifier unit is thus either a MEMS amplifier unit or a MEMS transducer amplifier unit. For the sake of simplicity, the MEMS transducer can be referred to as a transducer in the following text.

[0009] The amplifier unit can be used, for example, to implement active noise reduction (ANR) or active compensation for ambient noise. The transducer and the amplifier unit that drives the transducer are located, for example, in headphones, headsets, in-ear headphones, helmets with headphones, or mobile phones to provide the wearer or user with higher quality music, sound, and / or speech by reducing ambient noise. In ANR, ambient noise is canceled out using anti-noise. Active compensation is characterized by the fact that ambient noise is canceled out using anti-noise. Passive compensation of ambient noise could be achieved, for example, through sound isolation of the headphones.

[0010] Furthermore, the amplifier unit includes at least one audio amplifier for sound reproduction and / or sound recording. The audio amplifier can, for example, process and / or condition the sound signals picked up by the transducer when the latter is operated as a microphone. For instance, the audio amplifier can process the sound signals in such a way that they can be stored digitally.

[0011] The audio amplifier can, for example, process incoming audio signals when the transducer is used as a loudspeaker. The audio amplifier can process and / or condition these audio signals so that the transducer can convert them into sound waves, such as tones, music, and / or speech.

[0012] According to the invention, the amplifier unit is designed such that the transducer provided for this purpose can be operated simultaneously as a loudspeaker and as a microphone. The simultaneous operation of the transducer as a loudspeaker and as a microphone can, for example, mean that a wearer of the headphones in which the amplifier unit is arranged gets the impression that the transducer can simultaneously reproduce sound as a loudspeaker and record sound as a microphone.

[0013] As described above, in the "active noise reduction" method, ambient noise is picked up by a microphone. From this, anti-noise is generated, which is preferably played simultaneously with the music from a speaker in the headphones. The anti-noise component of the music interferes with the ambient noise and cancels it out. Only the music remains, and the user does not hear the ambient noise. In particular, the ambient noise can be picked up using the transducer, and the corresponding anti-noise can be played back along with the music at the same time. The ambient noise and the anti-noise cancel each other out through destructive interference, so that only the music remains.

[0014] By simultaneously operating the transducer as a microphone and loudspeaker, it is advantageously possible to dispense with a separate microphone for recording ambient noise or a loudspeaker solely for outputting the anti-noise, since the transducer of the amplifier unit according to the invention simultaneously records the ambient noise and plays the corresponding anti-noise in addition to the music. This allows the ANR method to be implemented with only one transducer, thus enabling more economical headphone production. By recording the sound, particularly the ambient noise, and reproducing the music by the transducer at a single location, the sound quality is enhanced. With a single transducer acting as both a loudspeaker and microphone, the anti-noise is generated at the location where the corresponding ambient noise is present, ensuring that the anti-noise is precisely matched to the surrounding ambient noise.

[0015] Furthermore, the ANR process can be carried out faster, since the travel time of the sound between the location where the ambient noise is recorded and the location where the anti-sound is played back does not have to be taken into account.

[0016] In an advantageous embodiment of the invention, the amplifier unit includes a processor by means of which the intended sound transducer can be used simultaneously as a microphone during sound generation. The processor can also be designed as a digital signal processor. For example, the processor can include a computing unit in which a computer program is executed that filters out the ambient noise from the recorded sound signal and generates the anti-sound from it. The processor can also operate the at least one audio amplifier. Advantageously, the processor can direct the anti-sound to the audio amplifier, which is connected to the sound transducer for sound reproduction, in order to play back the anti-sound, preferably along with the music.

[0017] It is also advantageous if the noise-canceling processor is designed to filter out and / or suppress ambient noise based on the emitted audio signal and the sound signal simultaneously captured by the same transducer. The processor generates anti-sound from the ambient noise and feeds it back to the transducer, which then plays the anti-sound along with the music.

[0018] It is advantageous if the processor is designed to separate an audio signal, captured by the MEMS transducer acting as a microphone, into a first component representing the emitted sound and a second component representing ambient noise. The desired sound includes, for example, music, tones, and speech intended for a listener. Ambient noise, on the other hand, is interference. This allows the ambient noise to be further processed. From this ambient noise, an anti-sound can be generated, which cancels out the ambient noise.

[0019] Advantageously, ambient noise can be filtered out or separated from the captured sound signal by generating a difference signal. Since, when the transducer is simultaneously operating as a loudspeaker and a microphone, the sound signals captured by the transducer as a microphone contain both ambient noise and the desired sound, the ambient noise can be separated from the captured sound signal by calculating the difference. The desired sound is known because it corresponds to the audio signal generated by the loudspeaker. The captured sound signal thus contains a first sound signal component, which originates from the sound waves generated according to the audio signal and comprises the desired sound, and a second sound signal component, which originates from the ambient noise. For example, the first sound signal component can be filtered out of the sound signal.The first sound signal component is separated, specifically subtracted from the first, so that only the second component, which includes the ambient noise, remains. An advantage of this is that the first sound signal component is known, as it corresponds to the audio signal according to which the sound waves, which in turn contain at least music, tones, and speech, are generated.

[0020] Furthermore, it is advantageous if the processor is designed to generate an anti-noise signal from the second component of the sound signal and combine this with an input signal containing the desired sound to create the audio signal. The input signal could, for example, be speech, music, or tones. The input signal could, for instance, originate from a music file. The processor can also generate the anti-noise signal, which cancels out the ambient noise when sound waves are produced from it. Furthermore, the processor can combine the anti-noise signal and the input signal into the audio signal, which is sent to the MEMS transducer, which generates corresponding sound waves. These then contain the desired sound, comprising the music, tones, or speech, and the anti-noise that cancels out the ambient noise.

[0021] Furthermore, it is advantageous if the processor is designed to switch the MEMS transducer between operation as a loudspeaker and operation as a microphone. For this purpose, the processor can, for example, include a switching unit that can switch the transducer between these modes. If the processor switches sufficiently quickly between operating the transducer as a loudspeaker and operating as a microphone, this can create the impression for a person that the transducer is operating simultaneously as both a loudspeaker and a microphone. For example, the transducer can operate as a loudspeaker during a loudspeaker interval and as a microphone during a microphone interval. Advantageously, the loudspeaker and microphone intervals can alternate.If these two intervals alternate quickly enough, it can be perceived as if the transducer is simultaneously generating and capturing the sound waves. The processor can switch between the speaker interval and the microphone interval.

[0022] It is also advantageous if the amplifier unit includes a hybrid audio amplifier, which can output the audio signal to the designated transducer for sound reproduction and simultaneously receive the sound signal from the transducer for sound recording. The hybrid audio amplifier is thus designed to send the audio signal to the transducer and simultaneously receive the sound signal, containing both music and ambient noise, from the same transducer. The hybrid audio amplifier can be connected to the transducer via a single audio cable.

[0023] It is also advantageous if the amplifier unit includes a speaker amplifier for reproducing the audio signal and a microphone amplifier for receiving the sound signal. This allows each amplifier to be specialized for its respective task. The speaker amplifier can be optimized to prepare the audio signal for sound reproduction by the transducer. The microphone amplifier can also be optimized to process the sound signal picked up by the microphone. Since the sound signal contains both music and ambient noise, the microphone amplifier can be optimized to separate the ambient noise from the music. The ambient noise can then be processed to generate anti-sound. Each of the two amplifiers can be individually connected to the transducer via audio cables.Alternatively, the two audio lines coming from the amplifiers can be joined together first, so that only one audio line leads to the transducer.

[0024] Furthermore, it is advantageous if the audio amplifier is designed to operate a MEMS transducer. The MEMS transducer can also be a piezoelectric MEMS transducer. MEMS transducers can be designed to be particularly compact and have low power consumption, allowing, for example, battery-powered headphones to have a long operating time. In addition, the MEMS transducer can easily be operated as a loudspeaker using electrical signals. Moreover, the piezoelectric MEMS transducer, in particular, directly generates an electrical sound signal when used as a microphone, which can then be processed directly by the audio amplifier.

[0025] Furthermore, it is advantageous if the amplifier unit includes at least one signal processing unit connected to the at least one audio amplifier. The signal processing unit allows the audio signal to be prepared for sound reproduction. For example, the signal processing unit can filter, pre-amplify, and / or modulate the audio signal so that the audio amplifier can then send it to the transducer for sound reproduction.

[0026] Additionally or alternatively, the sound signal can be processed for recording using the signal processing unit. For this purpose, the signal processing unit can, for example, filter, pre-amplify, modulate, digitize, and / or store the sound signal. The signal processing unit can also be designed, for example, to separate the ambient noise contained in the sound signal from the music. The signal processing unit can also generate anti-sound that matches the ambient noise. The signal processing unit can also feed the anti-sound to the loudspeaker amplifier, so that it plays the music with the anti-sound to cancel out the ambient noise.

[0027] It is also advantageous if the processor has a data connection to at least one audio amplifier. Additionally or alternatively, the processor can also have a data connection to at least one signal processing unit. The data connection allows the transmitted audio signals, the captured sound signals, and the audio data to be processed in the signal processing unit to be sent to the processor. The data connection can also be bidirectional, allowing data to be transmitted in both directions.

[0028] The data connection can also be designed as a conductor track on a circuit board.

[0029] It is also advantageous if the amplifier unit has at least one interface through which audio signals can be transmitted from the amplifier unit to the transducer and sound signals from the transducer to the amplifier unit, preferably simultaneously. The interface can be wired and / or bidirectional. For example, the interface can be a jack plug, an RCA plug, an XLR plug, a Speakon connector, and / or a USB connection. Such an interface allows the transducer to be detachably connected to the amplifier unit. Alternatively, the interface can be a soldered connection, so that the transducer is permanently attached to the amplifier unit.

[0030] It is also advantageous if the amplifier unit is integrated onto a single chip. This allows the amplifier unit to be combined with the audio amplifier, signal processing unit, processor, and / or data connections on a single chip. The amplifier unit can then be integrated into a particularly space-saving ASIC.

[0031] Furthermore, a sound generation unit is proposed, comprising a transducer that can be operated as both a microphone and a loudspeaker. The sound generation unit also includes an amplifier unit coupled to the transducer for sound reproduction and / or sound recording.

[0032] The sound generation unit can be located, for example, in headphones, headsets, in-ear headphones and / or mobile phones.

[0033] The amplifier unit is designed according to one or more features of the preceding and / or following description.

[0034] In an advantageous further development of the sound generation unit, the transducer is designed as a simultaneous transducer, which can emit an audio signal while functioning as a loudspeaker and simultaneously receive a sound signal while functioning as a microphone. "Simultaneously" can also mean that a listener perceives the simultaneous transducer as recording sound, particularly ambient noise, as a microphone, while simultaneously emitting music, particularly anti-sound, as a loudspeaker.

[0035] It is particularly advantageous if the transducer is a piezoelectric MEMS transducer. The piezoelectric MEMS transducer can be designed to be especially compact and has low power consumption, allowing the sound generation unit to operate energy-efficiently. Furthermore, the piezoelectric MEMS transducer can be driven very easily with the audio signal.

[0036] It is also advantageous to integrate the amplifier and transducer onto a single chip. This allows the sound generation unit to be manufactured as a single component, for example, on an ASIC. Furthermore, in an ASIC, for instance, the connection paths between components, such as between the processor and at least one audio amplifier, can be kept short, thus reducing the processing speed of the audio data. When the sound generation unit is on a single chip, the data connections between the components can be implemented directly on the chip using simple traces.

[0037] Furthermore, the sound transducer comprises at least one transducer unit coupled to a diaphragm of the transducer. This unit can deflect the diaphragm to generate sound and detect its deflection to capture sound. The transducer unit can include a transducer element, which, for example, exhibits piezoelectric properties. This allows the transducer element to be deflected by applying an electrical signal, such as the audio signal. Additionally, deflection of the transducer element can generate an electrical signal, such as the sound signal. The transducer element can also be coupled to the diaphragm via a coupling element, enabling the transmission of deflections between the transducer element and the diaphragm. When these deflections are transmitted from the transducer unit to the diaphragm, sound waves are generated.When the deflections from the diaphragm are transferred to the sound transducer unit, the sound waves are detected.

[0038] Furthermore, it is advantageous if at least one transducer unit has at least two transducer layers, with one transducer layer being used to deflect the diaphragm and the other layer being used to detect the diaphragm's deflection. One transducer layer can be operated as a loudspeaker and the other as a microphone. This allows a single transducer unit to function simultaneously as both a loudspeaker and a microphone. Additionally, the transducer layers can be connected to at least one audio amplifier. Alternatively, or in addition, the transducer layers can also be connected to the amplifier unit's processor. For example, if the first transducer layer is operated as a loudspeaker, it can be connected to the loudspeaker amplifier.Additionally or alternatively, the second transducer layer can be operated as a microphone and connected to the microphone amplifier.

[0039] Advantageously, at least two layers of sound transducers are arranged one above the other in the direction of the stroke axis. This ensures that both layers of sound transducers deflect evenly.

[0040] Furthermore, it is advantageous if at least one transducer unit is connected to the amplifier unit's processor, allowing the processor to deflect the diaphragm for sound generation and to detect the deflection. This enables the processor, for example, to switch the transducer unit between operation as a loudspeaker and operation as a microphone. Additionally or alternatively, at least one of the two transducer layers can also be connected to the amplifier unit's processor, allowing the processor to deflect the diaphragm for sound generation and to detect the deflection.

[0041] Furthermore, it is advantageous if the at least two transducer units of the transducer are coupled to each other by means of a connecting element. The connecting element can advantageously be elastic. This allows, for example, the excursions of one transducer unit, which is operated as a loudspeaker, to be transmitted to the other transducer unit, which is operated as a microphone.

[0042] It is also advantageous if the transducer has a limiting element that restricts the diaphragm's vibration in at least one direction along the transducer's axis of travel. This limiting element is fixed relative to the diaphragm. For example, the limiting element can be formed as a single unit with a support element of the transducer. The limiting element can be arranged such that, when the diaphragm vibrates in one direction, it abuts the limiting element. This limits the vibration in at least one direction along the axis of travel. Additionally, the diaphragm can be connected to the limiting element, thus limiting its vibration in both directions along the axis of travel. For this purpose, the diaphragm can, for example, be glued to the limiting element.The limiting element can also have a groove into which the diaphragm is inserted, thus limiting the diaphragm's oscillation in both directions along its axis. Naturally, the diaphragm's oscillation is only limited within the area of ​​the limiting element. Adjacent to the limiting element, the diaphragm can continue to oscillate. However, the limiting element effectively divides the diaphragm into two diaphragm sections.

[0043] It is advantageous if the diaphragm has a first and a second diaphragm area, with one transducer unit deflecting the diaphragm in the first area to generate sound, and the other transducer unit detecting the deflection of the diaphragm in the second area to capture the sound. The two diaphragm areas can be separated, for example, by the boundary element. This allows the transducer to be operated simultaneously as a loudspeaker and a microphone. Furthermore, it allows the transducer to be operated with a single diaphragm.

[0044] Furthermore, the limiting element can be arranged between the at least two transducer units. This allows each transducer unit to be located in a separate diaphragm area, so that, for example, the diaphragm in the first diaphragm area can be operated as a loudspeaker and in the second diaphragm area as a microphone.

[0045] Further advantages of the invention are described in the following exemplary embodiments. These show: Figure 1 a block diagram of an amplifier unit with two audio amplifiers, a processor and two signal processing units, Figure 2 a block diagram of an alternative embodiment of an amplifier unit with two audio amplifiers, a processor and two signal processing units, Figure 3 a block diagram of an alternative embodiment of an amplifier unit with a hybrid audio amplifier, a processor and two signal processing units, Figure 4 a schematic sectional view of a sound transducer with a support element and a diaphragm, Figure 5 a schematic sectional view of another embodiment of a sound transducer, Figure 6 a schematic sectional view of another embodiment of a sound transducer, and Figure 7A schematic sectional view of another embodiment of a sound transducer.

[0046] Figure 1 Figure 1 shows a block diagram of an amplifier unit 1 for operating a sound transducer 2, comprising two audio amplifiers 3a and 3b, a processor 4, and two signal processing units 5a and 5b. In this embodiment, audio amplifier 3a is configured as a loudspeaker amplifier, amplifying an audio signal for the sound transducer 2 so that the transducer 2 can be operated as a loudspeaker. Audio amplifier 3b, in this embodiment, is configured as a microphone amplifier, amplifying a sound signal from the sound transducer 2 so that the sound transducer 2 can be operated as a microphone.

[0047] Furthermore, in this embodiment, the audio amplifier 3a and the signal processing unit 5a are combined to form a loudspeaker unit 6, and the audio amplifier 3b and the signal processing unit 5b are combined to form a microphone unit 7. For example, the loudspeaker unit 6 and / or the microphone unit 7 can be manufactured as a single component, particularly on a single chip, which are assembled to form the amplifier unit 1.

[0048] The amplifier unit 1 has an audio input 8 for feeding in an audio signal, such as music and / or speech, which leads to the speaker unit 9 and / or the signal processing unit 5b. Alternatively, the audio input 8 can also feed the audio signal directly into the speaker amplifier 3b. The audio input 8 can, for example, feed a music signal from an MP3 player, a CD player, and / or a radio signal, such as from a mobile phone, into the amplifier unit 1.

[0049] For outputting the audio signal, the amplifier unit 1 has an audio output 9, which leads from the microphone unit 7 and / or from the signal processing unit 5a. The audio output 9 can also route the music or speech signal to a storage unit and / or to a mobile phone, where it is stored or sent to a conversation partner.

[0050] The audio input 8 and the audio output 9 may also have an interface not shown here, so that the audio signal can be, for example, introduced into and / or output via cable into the amplifier unit 1.

[0051] To connect the transducer 2 to the amplifier unit 1, the latter has an interface 10. Interface 10 and / or the interfaces of the audio input 8 and / or the audio output 9 can be wired and / or bidirectional and / or configured, for example, as a jack plug, an RCA plug, an XLR plug, a Speakon connector, and / or a USB connection, so that, for example, the transducer 2 can be detachably connected to the amplifier unit 1. The interfaces can also be optical, either additionally or alternatively.

[0052] Additionally or alternatively, the sound transducer 2 can also be permanently coupled to interface 10 by means of a soldered connection.

[0053] In this embodiment, the processor 4 is arranged between the audio amplifier 3a and the audio amplifier 3b, and is connected to both audio amplifiers 3a and 3b via data connections 11 (for simplicity, only one data connection is provided with a reference numeral). Furthermore, a data connection 11 leads from the processor 4 to the interface 10.

[0054] The data connection 11 can also be wired and / or bidirectional. The data connection 11 can be configured to transmit an electrical and / or optical signal. Furthermore, the data connection 11 can also be implemented as a conductor track on a printed circuit board.

[0055] The amplifier unit 1 can also be located, for example, in headphones, a headset, in-ear headphones, a helmet with speaker(s), or a mobile phone, whereby the amplifier unit 1 enables the transducer 2 to play and / or record music, a sound, and / or speech. If music is to be recorded, the transducer 2 can be used as a microphone. If music is to be played back, the transducer 2 can be used as a loudspeaker.

[0056] The amplifier unit 1 according to the invention can also be used to implement an "active noise reduction" (ANR) method. For this purpose, the amplifier unit 1 is designed such that it can operate the sound transducer 2 as a microphone for sound reception and simultaneously as a loudspeaker for sound reproduction.

[0057] Simultaneous can also mean that only the listener of the music, sound, or speech gets the impression that the cancellation of the ambient noise by the anti-sound is instantaneous. For example, due to the finite temporal resolution of human hearing, it may be sufficient if the cancellation of the ambient noise by the anti-sound occurs within the shortest temporal resolution of human hearing.

[0058] By means of the processor 4, which can also be designed as a digital signal processor, the sound transducer 2 can be used simultaneously as a microphone during sound generation.

[0059] For example, processor 4 can include a processing unit in which a computer program is executed that processes the sound picked up by transducer 2. Processor 4 can, for instance, filter out the ambient noise from the picked-up sound. Processor 4 can also generate anti-sound from the ambient noise, which is played back through transducer 2 along with the music and cancels out the ambient noise. The playback of the music and the anti-sound can occur simultaneously with the pickup of the ambient noise, so that the ambient noise is essentially canceled out immediately by the corresponding anti-sound.

[0060] As a microphone, transducer 2 picks up, for example, music and ambient noise. Amplifier unit 1 isolates the ambient noise and generates a corresponding anti-sound. This anti-sound, along with the music being played, is reproduced by transducer 2, which now functions as a loudspeaker. The anti-sound can be played back simultaneously with the ambient noise through transducer 2. The anti-sound component of the generated sound interferes destructively with the ambient noise, canceling it out. Only the music remains, which is perceived by the listener.

[0061] By capturing the sound, which includes ambient noise, and simultaneously generating the sound using a single transducer 2, the active noise reduction process can be performed with high quality. The cancellation of the ambient noise by the corresponding anti-sound is achieved by the single transducer 2 at the same location where the ambient noise is captured. This eliminates the need to factor in travel times between the location where the ambient noise is captured and the anti-sound is generated, thus enabling faster calculation of the anti-sound.

[0062] However, the amplifier unit 1 can also be manufactured on a single chip in one manufacturing step. For example, the audio amplifiers 3a, 3b, the processor 4, the signal processing units 5a, 5b and / or the data connections 11 can be arranged on the chip. Additionally or alternatively, the interface 10 and / or the interfaces of the audio input 8 and / or the audio output 9 can also be arranged on the chip.

[0063] Figure 2 An alternative embodiment of amplifier unit 1 is shown in a block diagram. Figure 1For the sake of simplicity, identical features and functions will not be described again here. In this embodiment, the processor 4 is arranged between the loudspeaker unit 6 and the microphone unit 7. The processor 4 has a data connection 11 to both the loudspeaker unit 6 and the microphone unit 7. The processor 4 is connected via the data connection 11 between the signal processing unit 5a and the audio amplifier 3a. Furthermore, the processor 4 is connected via the data connection 11 between the signal processing unit 5b and the audio amplifier 3b.

[0064] In this embodiment, the processor 4 can further process the sound processed by the audio amplifier 3b, which contains in particular the ambient noise and the music. Specifically, the processor 4 can generate the anti-sound from the ambient noise. The processor 4 can then direct the anti-sound to the loudspeaker unit 6, where the anti-sound is directed by the audio amplifier 3a to the transducer 2 for sound reproduction.

[0065] Figure 3 Figure 1 shows another alternative embodiment of the amplifier unit 1 with a sound transducer 2, a hybrid audio amplifier 3c, a processor 4 and two signal processing units 5a, 5b.

[0066] In this embodiment, the amplifier unit 1 comprises a single hybrid audio amplifier 3c, which can amplify the audio signal for sound reproduction in order to supply it to the transducer 2 and, in particular, simultaneously with sound recording, can process the sound signal from the transducer 2, for example, to store it. The hybrid audio amplifier 3c can, for example, also filter out the ambient noise from the recorded sound signal and generate the anti-sound from it. The hybrid audio amplifier 3c can also amplify the anti-sound again and supply it to the transducer 2 together with the music for sound reproduction. Additionally or alternatively, the processor 4 can also filter out the ambient noise from the recorded sound signal and generate the anti-sound.

[0067] Figure 4Figure 1 shows a schematic sectional view of a sound transducer 2 with a support element 12 and a diaphragm 13. The sound transducer 2 has a support element 12 on which a diaphragm 13 is arranged. The diaphragm 13 can cause air above it to vibrate, thus generating sound waves. The sound transducer 2 is thereby operated as a loudspeaker. Additionally, air above the diaphragm 13, vibrating as a result of the sound waves, can also cause it to vibrate. The sound transducer 2 is thereby operated as a microphone. The diaphragm 13 can be deflected along a stroke axis 20.

[0068] According to the present embodiment, the sound transducer 2 has a first sound transducer unit 21 and a second sound transducer unit 22.

[0069] The first transducer unit 21 can further comprise a first transducer element 14, which in this case is connected to the diaphragm 13 by means of a first coupling element 16. The second transducer unit 22 can comprise a second transducer element 15, which in this case is connected to the diaphragm 13 by means of a second coupling element 17. The two coupling elements 16, 17 can be rigidly connected to the diaphragm 13.

[0070] In the present embodiment, a coupling plate 27, 28 is arranged between the coupling elements 16, 17 and the diaphragm 13. The respective coupling plate 27, 28 enables a planar transmission of the deflection between the diaphragm 13 and the respective transducer unit 21, 22.

[0071] The first and / or the second transducer element 14, 15 can, for example, include a piezoelectric element, so that an electrical signal can be converted into a displacement of the transducer element 14, 15 and / or a displacement of the transducer element 14, 15 into an electrical signal. Since the first and / or the second transducer element 14, 15 is connected to the diaphragm 13 by means of the corresponding coupling element 16, 17, the displacements of the transducer elements 14, 15 can be transmitted to the diaphragm 13 and / or the vibrations of the diaphragm 13 can be transmitted to the transducer elements 14, 15.

[0072] The first transducer unit 21 is operated as a loudspeaker. Sound waves are generated using the first transducer unit 21. The second transducer unit 22 is operated as a microphone. The sound waves are thus picked up by the second transducer unit 22. The first transducer unit 21 can be operated simultaneously with the second transducer unit 22, so that sound waves can be generated and recorded simultaneously with the second transducer. Since both transducer units 21 and 22 are coupled to a diaphragm 13, the sound waves can be generated and recorded using the second transducer.

[0073] For example, the first sound transducer unit 21 is operated as a loudspeaker, so that sound waves are generated based on an audio signal, which in turn can include music, tones and speech as well as anti-sound.

[0074] The second transducer unit 22 can, for example, be operated as a microphone, so that a sound signal is detected based on the sound waves. The detected sound signal can have two components. A first component can, for example, contain the ambient noise. Additionally, a second component can contain speech, tones, music, and / or anti-sound, which are simultaneously generated by the first transducer unit 21. The detected sound signal is thus composed of the first and second components. However, since the second component is known, as it corresponds to the audio signal generated at the first transducer unit 22, this second component can be filtered out from the sound signal. For example, the second component can be subtracted from the sound signal. A difference signal can then be determined.This allows the first sound signal component, which includes the ambient noise, to be determined.

[0075] The first sound transducer unit 21 is, according to the present embodiment, the Figure 4 The first transducer section 18 is arranged in a first transducer area 18. Additionally or alternatively, the second transducer unit 22 is arranged in a second transducer area 19, according to the present embodiment. The two transducer areas 18, 19 can be spaced apart by a distance A. Additionally or alternatively, the two transducer units 21, 22 can also be spaced apart by a distance A. This distance A also separates the coupling elements 16, 17, which transmit the displacement between the diaphragm 13 and the corresponding transducer elements 14, 15. As a result, the two transducer units 21, 22 have only a minimal influence on each other for generating and / or detecting the sound waves.

[0076] For example, the first transducer unit 21 is operated as a loudspeaker, generating sound waves. The coupling element 16 transmits the displacements of the first transducer element 14 in the first transducer section 18 to the diaphragm, which then vibrates accordingly. The second transducer unit 22 can be operated simultaneously with the first transducer unit 22 as a microphone. Sound waves cause the diaphragm 13 in the second transducer section 19 to vibrate, and these vibrations are transmitted to the second transducer element 15 by the coupling element 17. Thus, sound waves can be generated and recorded simultaneously with a single transducer 2.

[0077] Alternatively, both transducer units 21, 22 can be operated as loudspeakers and / or as microphones. For example, the two transducer units 21, 22 can be operated as loudspeakers in one loudspeaker interval and as microphones in a subsequent microphone interval.

[0078] Figure 5 Figure 2 shows a schematic sectional view of another embodiment of a sound transducer. For the sake of simplicity, the features that are the same as in the previous figures are not explained again.

[0079] For example, the diaphragm 13 in the first diaphragm area 25 can be set into vibration by the first transducer unit 21, thus generating sound waves. The diaphragm 13 is therefore used for the loudspeaker function of the transducer 2 in the first diaphragm area 25. In the second diaphragm area 26, sound waves can set the diaphragm 13 into vibration, which can be detected by the second transducer unit 22. The diaphragm 13 is therefore used for the microphone function of the transducer 2 in the second diaphragm area 26.

[0080] The membrane 13 can further comprise a first membrane region 25 and a second membrane region 26. According to the present embodiment, the two membrane regions 25, 26 are arranged adjacent to each other on the membrane 13. In this embodiment, the Figure 5 a boundary element 23 arranged.

[0081] The limiting element 23 restricts the deflection of the diaphragm 13 in the area of ​​the limiting element 23 along the stroke axis 20. For example, the diaphragm 13 can rest, particularly loosely, on the limiting element 23, thus preventing deflection along the stroke axis 20 in the direction of the limiting element 23. Additionally or alternatively, the diaphragm 13 can also be connected to the limiting element 23, so that deflection along the stroke axis 20 is limited in both directions. The diaphragm 13 can, for example, be glued to the limiting element 23. The limiting element 23 can, for example, be formed as a single unit with the support element 12.

[0082] The first transducer area 18 can be located in the first diaphragm area 25 and the second transducer area 19 can be located in the second diaphragm area 26.

[0083] Figure 6shows a schematic sectional view of another embodiment of a sound transducer 2.

[0084] According to the present embodiment, the two transducer units 21, 22 are connected to each other by means of a connecting element 23. The connecting element 23 couples the two transducer units 21, 22, so that the excursions of the transducer units 21, 22 are transmitted to the respective other transducer unit 21, 22. According to the present embodiment, the connecting element 23 is arranged between the two coupling elements 16, 17 of the two transducer units 21, 22.

[0085] The connecting element 24 can also be elastically designed so that a change in the distance A caused by the deflection of the sound transducer elements 21, 22 can be compensated for. The connecting element 24 can, for example, have a spring element.

[0086] Furthermore, the first and / or the second transducer unit 21, 22 can be connected to at least one audio amplifier 3. For example, if the first transducer unit 21 is operated as a loudspeaker to generate the sound waves, it can be connected to the audio amplifier 3, which is operated as a loudspeaker amplifier. If the first transducer unit 21 is operated as a loudspeaker, it can, for example, be connected to the audio amplifier 3a of the Figure 1 and 2 be connected. For example, if the second transducer unit 22 is operated as a microphone to capture the sound waves, the second transducer unit 22 can also be connected to an audio amplifier 3. If the second transducer unit 22 is operated as a microphone, for example, it can be connected to the audio amplifier 3b of the Figure 1 and 2 be connected.

[0087] Figure 7 Figure 1 shows a schematic sectional view of another embodiment of a sound transducer 2. The embodiment with only one sound transducer unit 21, 22 is not part of the invention. According to the present embodiment, the sound transducer element 14 can have a first sound transducer layer 29 and a second sound transducer layer 30. Both sound transducer layers 29, 30 can form the sound transducer element 14. The two sound transducer layers 29, 30 can be arranged one above the other in the direction of the stroke axis 20. The two sound transducer layers 29, 30 can each be designed as a piezoelectric element. The first sound transducer element 14 of the present embodiment can be formed by two piezoelectric elements arranged one above the other.

[0088] It is advantageous if one of the two transducer layers 29, 30 is used to generate the sound waves as a loudspeaker and the other transducer layer 29, 30 is used to capture the sound waves as a microphone. Thus, one transducer layer 29, 30 can generate the sound waves and the other transducer layer 29, 30 can capture them.

[0089] The sound waves can thus be generated by, for example, the first sound transducer layer 29 and simultaneously detected by the second sound transducer unit 30.

[0090] The two transducer layers 29, 30 can also be connected to the respective audio amplifiers 3a, 3b. The transducer layer 29, 30, which is operated as a loudspeaker, can be connected to the audio amplifier 3a, 3b, which is operated as a loudspeaker amplifier, and the transducer layer 29, 30, which is operated as a microphone, can be connected to the audio amplifier 3a, 3b, which is operated as a microphone amplifier.

[0091] Alternatively, the sound transducer 2 can also have two sound transducer units 21, 22, similar to the preceding figures, with at least two sound transducer layers 29, 30.

[0092] The present invention is not limited to the embodiments shown and described. Modifications within the scope of the claims are possible, as is a combination of the features, even if these are shown and described in different embodiments. Reference symbol list

[0093] 1 Amplifier unit 2 MEMS transducer 3 Audio amplifier 4 Processor 5 Signal processing unit 6 Speaker unit 7 Microphone unit 8 Audio input 9 Audio output 10 Interface 11 Data connection 12 Carrier element 13 Diaphragm 14 First transducer element 15 Second transducer element 16 First coupling element 17 Second coupling element 18 First transducer section 19 Second transducer section 20 Stroke axis 21 First transducer unit 22 Second transducer unit 23 Limiting element 24 Connecting element 25 First diaphragm section 26 Second diaphragm section 27 First coupling plate 28 Second coupling plate 29 First transducer layer 30 Second transducer layer Distance

Claims

1. A sound generating unit having a MEMS sound transducer (2), which is operable as a microphone and as a loudspeaker, and having an audio amplifier unit (1) coupled to the MEMS transducer (2) for sound reproduction and sound recording, wherein the audio amplifier unit (1) comprises at least one amplifier (3a, 3b) for sound reproduction and sound recording, wherein the amplifier unit (1) is designed in such a way that the MEMS sound transducer (2) provided therefor is operable simultaneously as a loudspeaker and as a microphone and wherein the sound recording and simultaneous sound generation can be performed by a single MEMS sound transducer (2), characterized in that the MEMS sound transducer (2) comprises a first and second sound transducer unit (21, 22) coupled to a diaphragm (13) of the MEMS sound transducer (2), wherein the sound waves are generated by means of the first sound transducer unit (21) and recorded by means of the second sound transducer unit (22).

2. The sound-generating unit as claimed in the preceding claim, characterized in that the MEMS sound transducer (2) is designed as a simultaneous sound transducer, which, operating as a loudspeaker, can output an audio signal and, at the same time, operating as a microphone, can record an acoustic signal and / or the MEMS sound transducer (2) is a piezoelectric MEMS sound transducer and / or the amplifier unit (1) and the MEMS sound transducer (2) are arranged on a single chip.

3. The sound-generating unit as claimed in one or more of the preceding claims 1 to 2, characterized in that the two sound transducer unit (21, 22) comprise at least two sound transducer layers (29, 30), wherein the diaphragm (13) is deflectable with the aid of one sound transducer layer (29, 30) and the deflection of the diaphragm (13) is detectable with the aid of the other sound transducer layer.

4. The sound-generating unit as claimed in one or more of the preceding claims 1 to 3, characterized in that the both sound transducer unit (21, 22) and / or at least one of the two sound transducer layers (29, 30) are / is connected to a processor (4) of the amplifier unit (1), so that the processor (4) can deflect the diaphragm (13) for sound generation and can detect the deflection for sound detection with the aid of the both sound transducer unit (21, 22) and / or at least one of the two sound transducer layers (29, 30).

5. The sound-generating unit as claimed in one or more of the preceding claims 1 to 4, characterized in that the at least two sound transducer units (21, 22) of the MEMS sound transducer (2) are connected to one another with the aid of an, in particular, elastic connecting element (24) and / or the MEMS sound transducer (2) comprises a limiting element (23), with the aid of which the diaphragm (13) is limited in the deflection in at least one direction of a reciprocation axis (20) of the sound transducer (2).

6. The sound-generating unit as claimed in one or more of the preceding claims 1 to 5, characterized in that the diaphragm (13), in particular separated by the limiting element (23), comprises a first diaphragm area (25) and a second diaphragm area (26), wherein one of the sound transducer units (21, 22) can deflect the diaphragm (13) in the first diaphragm area (25) for sound generation and the other sound transducer unit (21, 22) can detect the deflection of the diaphragm (13) in the second diaphragm area (26) for sound recording.

7. The sound-generating unit as claimed in at least claim 4, characterized in that the amplifier unit (1) comprises a processor (4), in particular a digital signal processor, with the aid of which the MEMS sound transducer (2) provided therefor can be utilized as a microphone at the same time as the sound generation and / or the processor (4) is designed, for sound cancellation, in such a way that it can filter out and / or suppress ambient noise on the basis of the emitted audio signal and the acoustic signal detected at the same time with the aid of the same MEMS sound transducer (2).

8. The sound-generating unit as claimed in one or more of the preceding claims 4 to 7, characterized in that the processor (4) is designed in such a way that it separates an acoustic signal, which is detected by the MEMS sound transducer (2) operating as a microphone, into a first acoustic signal component representing the emitted useful sounds and into a second acoustic signal component representing the ambient noise and / or the processor (4) is designed in such a way that it generates an anti-noise signal on the basis of the second acoustic signal component and combines the anti-noise signal with an input signal including useful sound to form the audio signal.

9. The sound-generating unit as claimed in one or more of the preceding claims 4 to 8, characterized in that the processor (4) is designed in such a way that it can switch the MEMS sound transducer (2) between the operation as a loudspeaker and the operation as a microphone.

10. The sound-generating unit as claimed in one or more of the preceding claims 4 to 9, characterized in that the amplifier unit (1) comprises a hybrid audio amplifier (3c), with the aid of which the audio signal can be output to the MEMS sound transducer (2) provided therefor, for sound reproduction, and the acoustic signal of the MEMS sound transducer (2) can be received, for sound recording and / or the amplifier unit (1) comprises a loudspeaker amplifier (3a) for the sound reproduction of the audio signal and a microphone amplifier (3b) for the sound recording of the acoustic signal.

11. The sound-generating unit as claimed in one or more of the preceding claims 1 to 10, characterized in that the amplifier unit (1) comprises at least one signal processor (5a, 5b), which is connected to the at least one audio amplifier (3a, 3b) and with the aid of which the audio signal can be preconditioned for sound reproduction and / or the acoustic signal can be conditioned for sound recording.

12. The sound-generating unit as claimed in one or more of the preceding claims 4 to 11, characterized in that the processor (4) comprises a data link (11) to the at least one audio amplifier (3a, 3b) and / or to the at least one signal processor (5a, 5b), with the aid of which the emitted audio signals and detected acoustic signals and the audio data to be processed in the signal processor (5a, 5b) can be transmitted to the processor (4) and / or the amplifier unit (1) comprises at least one, in particular wired and / or bidirectional, interface (10), via which audio signals can be transmitted from the amplifier unit (1) to the MEMS sound transducer (2) and acoustic signals can be transmitted from the MEMS sound transducer (2) to the amplifier unit (1), preferably at the same time.